/**
 * 树节点类
 */
public class Node {
    public int val;
    /**
     * 左子节点
     */
    public Node left;

    /**
     * 右子节点
     */
    public Node right;

    /**
     * 右侧节点指针
     */
    public Node next;

    public Node() {

    }

    public Node(int _val) {
        val = _val;
    }

    public Node(int _val, Node _left, Node _right) {
        val = _val;
        left = _left;
        right = _right;
    }

    public Node(int _val, Node _left, Node _right, Node _next) {
        val = _val;
        left = _left;
        right = _right;
        next = _next;
    }
}
